A 1m X 1m X 1m concrete block is not a metric ton, it is not
water 
A 1m cube of hardened concrete is about 2.4 metric tons. They repeat this error a few times in the video actually
What other errors are there
The piers do look good though and I am sure a local machine/fab shop would have no problems constructing one similar if you provide them with a reasonable drawing. I would expect since it is a custom one off job the price will not be super cheap.
Mike